$color: red;

@mixin layout {
    display: flex;
    justify-content: space-between;
}

@mixin margin($value) {
    margin: $value;
}

.box1 {
    width: 100px;
    height: 100px;
    background-color: $color ;

    margin: {
        top: 10px;
        right: 20px;
        bottom: 30px;
    }

    @include layout;
}

.box2 {
    @include margin(10px);
}

.a {
    outline: none;
    width: 100px;
    margin: 10px;
}

%b {
    width: 50px;
    height: 50px;
    background-color: red;
}

input{
    @extend %b;
}